Part-66 OJT for an Aircraft Type Rating: Requirements, Task Selection and Sign-Off

A basic Part-66 licence does not automatically authorise an engineer to certify maintenance on every aircraft. To exercise certification privileges on a specific aircraft, the relevant aircraft type rating must be added to the licence. For the current regulatory framework, review EASA's Part-66 guidance and confirm the applicable requirements with the relevant competent authority.

For a first type rating in a particular Part-66 category or subcategory, this normally involves:

• Relevant aircraft type training
• Practical On-the-Job Training (OJT)
• Assessment and sign-off by an approved organisation and the competent authority

This guide explains how Part-66 OJT works, when it is required, how tasks should be selected and what evidence is needed for a first aircraft type rating.

What is Part-66 OJT?

Part-66 On-the-Job Training is structured practical training completed in a maintenance environment. It demonstrates that an engineer can apply theoretical knowledge and practical skills to real maintenance tasks on the aircraft type concerned.

OJT is not simply a record of general maintenance experience. It must be completed against an approved programme, using suitable aircraft and under the supervision of appropriately qualified personnel.

The training should demonstrate safe and competent performance across a representative range of tasks relevant to:

• The aircraft type
• The applicant's Part-66 licence category or subcategory
• The certification privileges being sought
• The maintenance environment in which the work is completed

Is OJT required for a basic Part-66 licence?

No. OJT is not required to obtain the basic EASA Part-66 aircraft maintenance licence.

The basic licence is obtained through examinations and practical maintenance experience under 66.A.30. OJT becomes mandatory when an applicant seeks to add a first aircraft type rating in a particular category or subcategory, in accordance with 66.A.45 and Appendix III. The applicable continuing airworthiness framework is summarised in EASA's continuing airworthiness information.

Examples include a first type rating in:

• B1.1, turbine aeroplanes
• B1.3, turbine helicopters
• B2, avionics
• L5, airships, subject to the applicable licence privileges

Once a first type rating has been established in a category or subcategory, the requirements for adding further aircraft types may differ. Applicants should confirm the applicable route with the competent authority that issued their licence.

What is needed to add an aircraft type rating?

To exercise certification privileges on a specific aircraft, the relevant aircraft rating must be endorsed on the Part-66 licence under 66.A.45.

For categories other than Category C, the usual requirements include:

• Completion of relevant aircraft type training to the standard specified in Part-66 Appendix III
• Completion of the corresponding OJT where it is the applicant's first type rating in that category or subcategory
• Satisfactory assessment of the OJT
• Submission of the required records and compliance documents to the competent authority

Category C applicants should check the specific requirements for their licence route. The first type OJT requirement does not apply in exactly the same way as it does to B1, B2 and other categories.

Where must OJT be completed?

First type OJT must be:

• Approved by the competent authority that issued the Part-66 licence
• Completed in an appropriately approved Part-145 maintenance organisation or Part-CAO
• Conducted under a controlled and documented OJT procedure
• Supervised and assessed by suitably qualified personnel

The organisation should have an OJT procedure in its Maintenance Organisation Exposition (MOE) or relevant Part-CAO documentation. Organisations and candidates should also consult the EASA Easy Access Rules for Continuing Airworthiness when checking the detailed regulatory and acceptable means of compliance material.

As a minimum, the procedure should explain:

• How the OJT programme is approved
• How candidates are selected and briefed
• How tasks are selected
• Who may act as supervisor and assessor
• How task performance is recorded
• How incomplete or failed tasks are managed
• How the final assessment and compliance report are completed
• How records are retained and made available to the authority

An organisation may have an established OJT programme for an aircraft type, but that does not automatically make the programme acceptable to every Part-66 authority. The programme must meet the requirements of the authority responsible for issuing the applicant's licence.

Applicants following a UK route should also check the UK CAA aircraft maintenance engineer guidance before committing to a programme.

Can OJT be completed outside the EASA Member States?

It may be possible to complete OJT in a Part-145 approved maintenance organisation whose principal place of business is outside the EASA Member States. The OJT must nevertheless be approved by the competent authority that issued the licence.

The endorsement of a first aircraft type rating in a category or subcategory requires satisfactory completion of the corresponding OJT under 66.A.45(c). Part-66 Appendix III, Section 6, requires the OJT to be approved by the licence-issuing authority.

Before beginning training outside the EASA Member States, obtain confirmation from the authority that:

• The maintenance organisation's approval is acceptable
• The proposed OJT programme is acceptable
• The aircraft and task mix are suitable
• The supervisors and assessor meet the required criteria
• The resulting records will support the first type application

Starting training before receiving this confirmation creates a significant risk that some or all of the OJT will later be rejected.

When must OJT be completed?

Part-66 Appendix III requires OJT to be started and completed within three years of the date of application.

The AMC to Appendix III also limits the amount of OJT that may be completed before theoretical type training. A maximum of 50% of the OJT may be completed before the theory training.

Applicants should therefore not complete the entire practical programme before attending the relevant aircraft type course. The programme should schedule the theory and practical elements in the correct order.

OJT that does not meet these timing requirements may be rejected by the competent authority.

How are OJT tasks selected?

Task selection is one of the most important parts of the programme. The AMC to Appendix III requires tasks to be representative of the licence category or subcategory being applied for.

Tasks must reflect both the aircraft and the privileges of the applicant. For example:

• A B1.1 programme should include suitable mechanical, powerplant and systems tasks on a turbine aeroplane.
• A B1.3 programme should reflect the systems and maintenance environment of a turbine helicopter.
• A B2 programme should focus on avionics, electrical systems, communications, navigation, instruments and related troubleshooting.
• A licence category with limited privileges should not be assessed against tasks outside those privileges.

The task list should identify the relevant licence category or subcategory. A generic list of aircraft maintenance tasks is unlikely to be sufficient unless it clearly demonstrates relevance to the application.

Characteristics of a good task list

A well-designed OJT task list should contain a suitable mixture of:

• Scheduled maintenance
• Unscheduled maintenance
• System testing
• Fault isolation and rectification
• Component removal and installation
• Operational or functional checks
• Inspections
• Servicing
• Rigging or adjustment, where applicable
• Use of maintenance data and technical publications
• Accurate completion of maintenance records

The programme should demonstrate diversity as well as quantity. Repeating the same simple task does not necessarily demonstrate competence across the aircraft type.

Can tasks be completed on another aircraft type?

In some cases, a limited number of tasks may be performed on another aircraft type, typically one from the same manufacturer. This should be accepted only where the task is sufficiently similar to the task applicable to the aircraft type for which the applicant is seeking an endorsement.

The AMC to Section 6 of Appendix III states: "Tasks should be selected among those applicable to type of aircraft and licence (sub)category applied for."

Tasks applicable to the target aircraft type may also be found on other aircraft. However, using another aircraft type must be justified, rather than treated as a way to avoid aircraft-specific tasks.

The organisation and assessor should consider:

• Whether the systems operate in a genuinely similar way
• Whether the maintenance task uses comparable procedures
• Whether the same type of technical judgement is required
• Whether the task demonstrates a skill relevant to the requested rating
• Whether the task is sufficiently representative of the target aircraft

The final programme should still contain enough tasks completed on the aircraft type concerned to demonstrate type-specific competence.

Who supervises the OJT?

OJT tasks must be completed under the supervision of personnel who are suitably qualified and authorised by the organisation.

The supervisor should be able to:

• Confirm that the task is appropriate
• Brief the candidate before work begins
• Observe the candidate performing the task
• Ensure that current approved maintenance data is used
• Intervene when safety or technical standards require it
• Confirm whether the task was completed satisfactorily
• Provide accurate feedback in the OJT records

A supervisor's signature confirms that the task was observed or otherwise adequately verified. It does not replace the final assessment by the appointed OJT assessor.

What does the assessor do?

The assessor performs the final review of the OJT programme and determines whether the candidate has completed the required training to an acceptable standard.

The assessment should consider:

• The required quantity and diversity of tasks
• The relevance of the tasks to the aircraft type
• The relevance of the tasks to the licence category or subcategory
• Supervisor reports and feedback
• The candidate's ability to use maintenance data
• The quality and accuracy of the records
• The candidate's approach to safety and aircraft protection
• The candidate's ability to complete and document maintenance correctly

The assessor should be sufficiently independent to make an objective judgement and must meet the competence requirements established by the approved organisation and competent authority.

What is the OJT sign-off process?

1. Programme approval

The organisation prepares or adopts an OJT programme covering the aircraft type and licence category. Where required, the programme is submitted to the competent authority.

2. Candidate briefing

The candidate is briefed on the programme scope, task mix, recording method, supervisor responsibilities, assessment arrangements, time limits and theory-training restrictions.

3. Task completion

The candidate performs tasks under supervision using current approved maintenance data.

Each task record should normally include:

• Aircraft registration or identification
• Date of completion
• Work order or task reference
• Maintenance document reference
• Description of the task
• Candidate's name and licence details
• Supervisor's name, authorisation and signature
• Result or outcome
• Relevant comments or limitations

4. Supervisor feedback

Supervisors provide feedback on the candidate's practical performance. Any task that is incomplete, incorrectly recorded or not performed to the required standard should be addressed before the final assessment.

For practical guidance on maintaining supporting evidence, review how to fill out a CAP 741 logbook and avoid the common logbook mistakes that delay applications.

5. Assessor review

The assessor reviews the complete record and confirms whether the programme demonstrates the required diversity and quantity of OJT.

6. Compliance report

The assessor normally completes a Compliance Report or equivalent final assessment document. This report supports the application for the first aircraft type rating and may be required by the CAA or another competent authority.

7. Application to the authority

The candidate submits the OJT evidence, compliance report, type training evidence and other required documents to the authority that issued the Part-66 licence.

The authority makes the final decision on whether the evidence supports endorsement of the type rating.

Common reasons OJT is rejected

OJT may be rejected or returned for correction when:

• The programme was not approved by the licence-issuing authority.
• The organisation was not an appropriately approved Part-145 or Part-CAO.
• The task list was not representative of the licence category.
• Too many tasks were completed before theory training.
• The three-year completion period was exceeded.
• Tasks were performed on an unsuitable aircraft type.
• Supervisor signatures or authorisations are missing.
• The records do not identify the aircraft or maintenance data used.
• The programme contains insufficient task diversity.
• The assessor's report is incomplete.
• The candidate completed tasks outside the organisation's approved procedure.
• The evidence does not clearly demonstrate competence on the target aircraft type.

Good administration is therefore as important as the practical work itself. Candidates who want specialist support with Part-66 records can analyse their logbook with Part 66 Logbook Analysis before submitting evidence.

Planning your first type-rating OJT

Before enrolling, ask the maintenance organisation or training provider:

• Is the OJT programme approved for my licence category?
• Has the programme been accepted by the authority that issued my licence?
• Is the organisation Part-145 or Part-CAO approved?
• Which aircraft registrations will be available?
• How many tasks can realistically be completed?
• Are the tasks sufficiently diverse?
• Who will supervise the work?
• Who will perform the final assessment?
• How are failed or repeated tasks recorded?
• Will I receive a completed compliance report?
• Are any tasks planned on another aircraft type, and why?
• Does the schedule comply with the 50% pre-theory restriction?

These questions can help prevent costly delays in the application process. If you still need the relevant theoretical preparation, use our directory of Part 147 training schools to research suitable providers.

Related aircraft maintenance training

Candidates may encounter additional technical and management courses while planning their professional development. For example:

• Airbus Aircraft Structure Repair and Maintenance, Basic: 3, 4, 5 and 6 November 2026, 09:00 to 16:00 CET, enrolment fee €1,500.
• Aircraft Maintenance Management: 28, 29 and 30 September 2026, 09:00 to 16:00 CEST, enrolment fee €700.
• Stores and Incoming Inspection: 12 October 2026, 09:00 to 16:00 CEST, enrolment fee €350.

These courses may be useful for professional development, but they should not be confused with the specific type training and first type OJT required for a Part-66 aircraft rating. Confirm what qualification or licence credit a course provides before enrolling.

Final checklist for compliant first type OJT

Before submitting the application, confirm that you have:

• A valid Part-66 basic licence
• Completed the relevant aircraft type training
• Completed the required first type OJT
• Used an approved Part-145 or Part-CAO organisation
• Received approval or acceptance from the correct competent authority
• Completed OJT within the required three-year period
• Completed no more than 50% of the OJT before theory training
• Completed tasks representative of the licence category or subcategory
• Recorded sufficient task diversity and quantity
• Obtained supervisor signatures and feedback
• Completed the final assessor review
• Received the required compliance report
• Prepared the full application package for the licence-issuing authority

Conclusion

Part-66 OJT connects aircraft type training with the practical ability to maintain and certify work on a specific aircraft. It is required for the first aircraft type rating in a category or subcategory, not for the basic Part-66 licence itself.

The strongest OJT programmes are carefully planned, approved by the relevant authority and matched to the candidate's licence privileges. Selecting suitable tasks, using qualified supervisors and maintaining complete records will support a successful first type-rating application.

Before starting, speak with both the approved maintenance organisation and the competent authority that issued the licence. Their confirmation should guide the programme, task selection and final sign-off.